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A99.9 F7622Uf 

United States 
Department of 

Forest Service 

Research Station 


Forests of the Garden State 

Richard H. Widmann 

Resource Bulletin NE-163 


RICHARD H. WIDMANN is a forester with the Northeastern Research Station's Forest 
Inventory and Analysis unit at Newtown Square, Pennsylvania ( ). 


I thank the New Jersey Department of Environmental Protection, Division of Parks and 
Forestry, for its cooperation and assistance, Jon Klischies for helpful comments and 
suggestions in reviewing an earlier draft of this report, and NE-FIA staff members Douglas M. 
Griffith, Tonya W. Lister, Andrew J. Lister, and Eric H. Wharton, whose contributions were 

Manuscript received for publication 8 October 2004 

Published by: For additional copies: 


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New Jersey's forests, a critical component of the State's natural resources, 
have been rich in history from colonial settlement to the present. In the 
Nation's most densely populated state, forests cover 45 percent of New Jersey's 
land mass and differ greatly in character from the coastal plain to the highlands 
region. These highly diverse forests provide globally significant biological 
communities, habitat for wildlife, forestry products, water quality, and 
opportunities for recreational. Although population growth and expansion 
into the rural environment have placed increased pressure on the State's forests, 
management professionals with the New Jersey Department of Environmental 
Protection's Forest Service continue to protect this valuable natural resource 
and provide sound stewardship to ensure that the broad range of benefits 
derived from these forests will be available to future generations. 

Forests of the Garden State 

Long known as the Garden State, New Jersey also is 
noted for lots of people, congested roads, suburban 
sprawl, and industrial development, all which have 
changed the character of the State over the last half 
century. Despite this change, much of the Garden State 
is forested — more than one might think. Like a garden, 
a forest produces valuable products and related benefits 
that must be tended and protected. Looking after this 
important resource requires a knowledge of current forest 
conditions and trends. To obtain this information, the 
USDA Forest Service periodically inventories the 
Nation's forests. In 1998, in cooperation with the New 
Jersey Department of Environmental Protection, 
Division of Parks and Forestry, researchers with the 
Northeastern Research Station's Forest Inventory and 
Analysis (FIA) unit completed the fourth survey of New 
Jersey's forests. This report summarizes the findings of 
the most current and previous inventories (1956, 1972, 
and 1987), as well as major changes that have occurred 
in the State's forests. 

Historical Perspective 

Settlers arriving in what is now New Jersey more than 
300 years ago followed the waters inland and were 
confronted with dense forests. Along the coastal plain to 
the south, there were extensive forests of pines and thick 
stands of Atlantic white-cedar. The settlers also 
encountered huge hardwood forests along the Delaware 
River, and vast forested hills and mountains in the 
northern region. The Native Americans who lived here 
had barely disturbed these forests; but the settlers- 
Dutch, Swedes, and English—needed land for farms and 
towns as well as wood to build houses and for items 
ranging from implements and fuel to pine tar, pitch, and 
timber for ships. And a growing population demanded 
that increasing amounts of land be cleared for growing 
crops and for pasture. So forests fell in New Jersey. By 
1860, many stands had been cut over many times — yet 
the cutting continued. Of course, some timber remained 
and new growth responded in cutover areas, but by the 
Civil War, lumber production peaked in the State as tree 
felling declined because of an ever dwindling supply. In 
northern New Jersey, residents began to use coal from 
Pennsylvania to heat their homes as firewood became 

Forest Inventory and Analysis field crews receive permission from 
private landowners before taking tree measurements on their land. 

more difficult to obtain. And in Philadelphia, builders 
obtained shingles from Maine to offset the scarcity of 
cedar. Fire that often followed timber cutting also slowed 
the natural recovery of New Jersey's forests. 

Today, forests now cover much of the State due to the 
sharp decrease in wood harvests beginning around 1860 
along with a corresponding decrease in the amount of 
acreage farmed. This recovery was aided by the rise of a 
conservation ethic that began in the late 1800's. Given a 
chance to grow under sound management, trees became 
reestablished naturally and relatively quickly in most 
regions of New Jersey. Efforts to control wildfires and 
low populations of white-tailed deer greatly facilitated 
this regeneration process. 

Jersey's residents have changed in how they look at and 
value forests. Originally, forests were seen as barriers to 
progress and needed to be cleared for settlement to occur. 
Timber products, fuelwood, and wild game were the 
major benefits received from the forest. Although these 
remain important, today's forest is valued and 
appreciated for amenities that enhance the quality of life: 
watershed protection, opportunities for recreation, 
conservation of wildlife habitat, diverse landscapes, and 
scenic beauty. 

About Forest Inventories 

Widespread abuse of land in the Eastern United States 
led to the passage by Congress of conservation legislation 


in the early part of the 20 th century. Under this and 
subsequent Acts, the Forest Service's FIA units initiated 
ongoing forest surveys of all states to provide current 
data about the Nation's forest resources. FIA provides 
objective and scientifically credible information on key 
forest ecosystem processes, for example, the amount of 
forest land and whether it is increasing or decreasing in 
area, changes in species composition, and the rate at 
which trees are growing, dying, or being harvested. Such 
data are invaluable to numerous users because they: 

• Help policymakers at both the federal and state 
level revise existing forest-management policies and 
formulate new ones, and enable land managers to 
better assess the effects of current and past 
management practices. 

• Serve as a starting point for a variety of scientific 
investigations of processes by which forest 
ecosystems change over time. 

• Keep the public informed as to the current health 
and sustainability of the Nation's forests. 

• Address important resource issues such as 
urbanization, forest fragmentation, invasive pest 
species, wildfire risk, global climate change, and 
water quality. 

FIA did not count every tree in inventorying New 
Jersey's forests. Instead, it used a scientifically designed 
sampling method. First, photointerpreters studied aerial 
photographs of the entire State. Then a grid of 17,000 
points was overlaid on the photos. Each of the points 
was classified as to land use and, if forested, the size of 
the trees. For New Jersey, a sample of 433 plots was 

Trend in New Jersey's Farm Acreage 


in 2 


< 1-5 




Land Use in New Jersey 

Forest land 

Farm land 

nonforest land 

1899 1950 1960 1970 1980 1990 2000 

Source: USDA National Agriculture Statistices Service 

selected for measurement. Included were plots 
established during previous inventories. By remeasuring 
these plots, data were obtained on how individual trees 
grow. Some plots that had been established nearly 50 
years ago were measured for the fourth time. Field crews 
collected information on a host of forest attributes, 
including the number, size, and species of trees. These 
data enabled FIA researchers to make reliable estimates 
of the current condition and overall health of New 
Jersey's forests, as well as the degree to which this vital 
resource is changing over time. 

Land Use and Forest Cover 

Extent of and Trends in Forest-Land Area 

Forests cover 45 percent of New Jersey, or 2.1 million 
acres. This amount of forest cover is remarkable for a 
state that has seen tremendous population growth and 
economic development during the last decade. The 
State's forest land has remained relatively stable because 
most of the population growth historically has 
been concentrated in areas adjacent to New York 
City, and because there has been a decrease in farm 
land. Land in farms is now less than half of what it 
was in 1956 — a loss of more than a million acres. 
Although much of what formerly was farm land 
has been developed, a substantial portion has been 
left untended and has reverted to forest through 
natural regeneration. These new forests have 
negated losses in forest to development. 



| 1.5 

* 1 


In addition, New Jersey is a national leader 
in protecting land by regulatory legislation. 
State planning has attempted to balance the 
need to conserve natural resources with the 
demands of a growing economy by 
promoting sustainable development. 
Conservation efforts to keep land in forests, 
farms, and other green space include both 
purchases of land and easements by the 
State and nongovernmental organizations. 
Conservation easements restrict future 
development while leaving the responsibility for 
management and ownership in private hands. By 
managing growth wisely, the adverse impacts of urban 
sprawl can be minimized in New Jersey. Still, despite 
these conservation efforts, a steady decline in forest-land 
area is likely throughout the State due to continued 
pressure placed on forests and farm land from 

Forest-land Area Trends 







99 1956 1972 1987 


□ Timberland ■ Other Forest Land 


The amount of timberland has not changed appreciably 
during the last three decades even though New Jerseys 
population increased by 15 percent (1.2 million) between 
1970 and 2000. 

The 1999 FLA forest inventory revealed that forest land 
in New Jersey increased by 143,900 acres since the 1987 
survey. This increase is attributed to the use of a more 
inclusive definition of forest land. Small forested areas in 
rights-of-way and in certain urban areas that previously 
were classified as nonforest were reclassified as forest. 
These areas are at least an acre in size, more than 120 feet 
wide, and stocked with trees. This change in inventory 
procedure was required because the value of all forest 
land is increasingly being recognized. Otherwise, there 
has been little change in the total forest land area in the 
State since the 1987 inventory. A separate survey by the 
National Resources Conservation Service showed a 
decrease in nonfederal rural forest land in New Jersey 
from 1987 to 1997. 

Forest land is categorized by the Forest Service as 
timberland or "other" forest land. These categories aid in 
understanding the availability of forest resources and 
forest management planning. Although New Jersey is not 
considered a timber-producing state, 88 percent of its 
forest land (nearly 1.9 million acres) is classified as 
timberland that is potentially available for harvesting. 

The other category of forest land includes reserved lands 
and unproductive forests. Harvesting for timber products 
on these lands is administratively restricted or 
economically impractical. Examples include parks, 
wildlife management areas, and wetlands where growing 
conditions are poor. Most of these forests are owned by 
public agencies. This category increased in area by nearly 
150,000 acres (to 256,100) from 1956 to 1999. Nearly 
all of this increase is attributed to the reclassification of 
timberland to reserve status where timber harvesting is 

Distribution of Forest Land 

Forested areas are not distributed evenly across the State. 
Sussex County is the most heavily forested (68 percent); 
Essex, Hudson, and Union Counties are the least 
forested. Generally, forests are concentrated in the 
northernmost portion of the State and in the Pine 
Barrens in Atlantic, Burlington, and Ocean, Counties in 
the south. Portions of the Pine Barrens also extend into 
the less forested counties of Camden, Cumberland, Cape 
May, and Gloucester. 


County Maps of FIA Data and Remotely Sensed Data 

Percentage of land Forest land distribution 

in forest by county (based on MRLC* 1992) 




People and Forests 
Urban Forests 

As the population of the Garden State continues to 
grow, the State's forests are becoming more 
urbanized. Urban forests are valued because they 
create more livable cities and towns, but frequently 
their value as habitat for wildlife and for ensuring 
biodiversity is impaired. The extent of urbanization 
can be depicted as a range of population densities. 
The urbanization map shows forest land by the 
population per square mile of the census block in 
which it occurs. The highest population densities 
are in those areas designated as urban by the U.S. 
Census Bureau. In addition to these designated 
urban areas, all forests in New Jersey are influenced 
by urbanization to some extent. In many instances, 
forests in areas with dense populations are on land 
that was initially rejected for development because 
the terrain was too wet, steep, or rocky. However, due to high prices for 
building lots and advanced building techniques, nearly all land is 
potentially suitable for development. Conservation efforts are focusing on 
identifying and preserving the most ecologically important of these urban 
forests. Areas with low population densities correspond to those with large 
public ownerships; Wharton State Forest in the south and Stokes and 
Worthington State Forests in the northwest portion of the State. 

Trend in New Jersey's Population 


1940 1960 
Census Year 



Source: U.S. Census Bureau 

Major changes currently affecting New Jersey's forests are the result of people: 
it is people who decide where to clear land for houses and people who 
intentionally or unintentionally allow land to revert to forest. Absent people, 
nearly all of the State would be forested-but New Jersey's population is nearly 
8.5 million and growing. How these people live on the land is a significant force 
in shaping the forest. New Jersey is the Nation's most densely populated state, 
yet it ranks ninth in the percentage of land area covered by forest. 


Fragmentation is Degrading 
Forest Habitats 

When a large portion of a forest is lost to new 
residential and urban development, the remaining 
forest land often is broken up into smaller tracts 
or noncontiguous patches. Known as forest 
fragmentation, this phenomenon is of growing 
concern to land managers and planners 
throughout the Northeastern United States. The 
fragmentation of forests, particularly by urban 
uses, degrades watersheds, reduces wildlife 
habitat, increases site disturbances, and favors 
invasion by exotic plant species. Many wildlife 
biologists believe that fragmentation is a 
contributing factor in the decline of some bird and 
wildlife species, though fragmentation favors species 
such as raccoons, squirrels, and white-tailed deer. 
These species are habitat generalists that have 
become acclimated to living near humans. 
Fragmentation also changes the character of rural 
areas because unlike owners of large tracts, owners 
of small parcels are less likely to manage their 
forests and/or allow access to their land for activities 
such as fishing and hunting. 

Forest Service scientists are attempting to 
characterize the distribution and fragmentation of 
forest land in New Jersey. One way to accomplish 
this is to determine the size of these forest patchs 
and their frequency. The State contains numerous 
patches that are 1 to 5 hectares (2.5 to 12.4 acres), 
but they represent only 5 percent of the total forest 
land. Three-quarters of New Jerseys forest land is in 
patches that exceed 100 hectares (247 acres). The 
largest patch, 5,726 hectares (14, 149 acres), is in 
Warren County. 

Urbanization of forest Land in New Jersey 

Forest land depicted as a 
range of population 
densities with Census- 
designated urban overlain. 


Forested 1 

■Q. - 

| 1-25 
I 1 25-50 

~J 50-100 
I I 100-250 

■ 250-500 

■ 500-1000 

■ >1000_^ 
H Urban area 

p=-People/sq mi 

High deer populations change the amount and composition of 
forest regeneration. They eat suburban landscaping and cause 
high numbers of traffic accidents in many areas of New Jersey. 

Forest Fragmentation 


'-5 5-70 ? 0-5 So -10 10o -SOo 500 -10oo 100 °*Ooo 

Patch Size Classes (hectares) 

D Number of patches □ Total area in class 

(1 hectare=2.47 acres) 


Average Forest Patch Size 

81 ac. 

50 ac. 

61 ac. 

33 ac. 

Bergen I 
Essex V- 33 ac. 
Hudson | 
Union I 

Middlesex V- 25 ac 
Mercer J 

30 ac. 

Development not only takes land out of forest but fragments 
the remaining forest habitat into small patches. 

31 ac. 


_ ,. Ocean 

3 64 ac. 

55 ac. 

27 ac. 

38 ac. 

Who Owns the Forest? 

New Jersey has the highest percentage of forest 
land in public ownership of any state east of the 

Mississippi River. But unlike many western states, the Garden State has no National 
Forests and little forest land in federal ownerships. The State owns more than 
500,000 acres of forest land — the largest ownership in New Jersey. However, this 
was not always the case. Because of public demand for recreation and clean water 
and a desire to keep parts of New Jersey undeveloped, State and local municipalities 
have been purchasing forest land and other open space. As a result, during the last 
half century, public ownership of forest land has more than 
doubled to 810,000 acres, increasing from 29 to 38 percent of 
forest land from 1987 to 1999. New Jersey is a leader in 
keeping land undeveloped for future generations to enjoy. 
Despite these increases in public ownership, the responsibility 
for managing the majority (62 percent) of New Jersey's forest 
land is in the hands of a large number of private owners. 
Recent estimates show that there are 89,000 forest-land owners 
in the State and their numbers are growing rapidly. They are 
represented by individuals, farmers, and corporations, 
including private land trusts. The reason for the rise in the 
numbers of forest-land owners is that large ownerships are 
being subdivided into smaller parcels to accommodate 
development. Owners have a wide range of reasons for owning 
land and diverse objectives in land management. Land trusts, 
whose holdings are increasing, work to keep land in forest by buying it outright or 
acquiring conservation easements that place restrictions on future use. 

Atlantic ~l 

Cape May/" 53 ac. 

Distribution of Forest Land Area by Ownership 






County and 





Public ownership of forest land provides 
recreational opportunities, protects water 
supplies, and preserves ecological values. 

Forest Structure and Composition Change Over Time 

As forests mature, the species composition at a particular site undergoes what ecologists call 
forest succession. During this process, long-lived plants that can tolerate shaded conditions 
replace short-lived plants that need full sunlight to thrive. This continuous process is 
influenced by disturbances from natural as well as human sources. Examples of disturbance 
occurring in New Jersey s forests include drought, fires, outbreaks insect pests such as the 
gypsy moth caterpillars, land clearing followed by abandonment, and logging. The 
interaction of these and other factors working over time have shaped the State's diverse forest 
resource. An understanding of the changes taking place in New Jersey's forest is helpful in 
fully appreciating this valuable resource and in making wise decisions regarding its future. 

New Jersey's Forests Are Maturing 

Many of the changes occurring in New Jersey's forests are 
associated with their age and maturation. Across the 
Northeastern States, forests are maturing as they recover from 
past land clearing and abuse. In the Garden State, many acres 
of forest land are abandoned farm lands that have naturally 
reverted to forest since the 1940s. Two-thirds of New Jersey's 
forests are younger than 60 years old. Because fewer acres of 
land are being allowed to revert, acreage in young stands will 
decrease. And once they mature, these stands will not be 
replaced. Maintaining forests that are well distributed across 
age classes enhances the biodiversity of the landscape and 
reduces the susceptibility to catastrophic damage. 

Age Distribution of New Jersey Forests, 1999 

0-20 21-40 41-60 61-80 81-100 100+ 
Age Class of Overstory Trees (years) 

Trees Have Increased in Size and Number 

How well forests are populated with trees is determined by measures of tree size and number. 
Foresters measure a tree at its diameters at AVi feet above the ground and refer to this as 


diameter at breast height (d.b.h.). Of trees 5 inches 
and larger in diameter, the average d.b.h. has 
increased from 8.2 to 8.9 inches since 1972. 
During this period, the average number of trees at 
least 5 inches in diameter has increased from 119 
to 161 per acre of timberland. Combined, these 
measures indicate that tree density has increased in 
New Jersey. 

Average Number of Trees Per Acre and Average Diameter 
(Trees 5 Inches and Greater d.b.h.) 

CD -Q 

0- E 

CO 3 

Forest Composition 

Changes in the numbers of trees have not been 
distributed evenly across diameter classes. Since 
1972, the numbers of saplings has decreased while 
the numbers of trees in all diameter classes above 5 
inches has increased. Combined, trees in the 2- and 4- 
inch diameter classes account for 70 percent of the trees 
at least 1 inch in d.b.h. Trees in the 6-, 8-, and 10-inch 
classes account for 24 percent; all trees 12 inches or 
larger account for 6 percent. The number of small trees 
declines as forests mature because the subsequent lack of 
sunlight reaching the forest floor inhibits the 
reproduction and growth of seedlings. 

When describing a forest, people speak of the species of 
trees growing there, e.g., a pine, oak, or beech forest. 
Foresters use the term forest type to describe groups of 
species that are frequently found growing in association 
with one another. The 1999 inventory identified 36 
forest types growing in the State. 


Courtesy of New Jersey Division of Parks and Forestry - New Jersey Forest Service 

The New Jersey Forest Fire Service puts out most wildfires before 
they can threaten communities and structures. Forests in the Pine 
Barrens are adapted to disturbance from fires and recover with time. 






























□ Average trees/acre ■ Average dbh 

Located primarily in the State's pinelands region and freshwater 
wetlands, Atlantic white-cedar swamps are essential storage areas 
for rainwater and water runoff. They help maintain productivity of 
wetland communities, provide essential habitat for wildlife and 
plant life, including threatened and endangered species, and add 
to the diversity and beauty of New Jersey's forest resource. 

Pitch pine is the dominate tree in the pinelands of southern New 


Similar forest types are combined into forest-type groups. 
Oak/hickory, the most common such group in the State, 
consists of well-known species such as white oak, northern 
red oak, hickory species, white ash, walnut, yellow-poplar, 
and red maple. The oak/hickory group covers two-thirds of 
New Jersey's forests. The pitch pine type, which is in the 
loblolly/shortleaf pine group, and the oak/pine group grow 
in the Pine Barrens in the southern part of the State. This 
area has a long history of wildfires, which promotes the 
growth of pine. Included in the oak/gum/cypress group are 
32,000 acres of Adantic white-cedar stands. Although 
covering too small an area to be captured by this inventory, 
some native red spruce grows in the extreme northwest 
portion of the State. These broad species groups, which have 
changed little in area since 1989, are another reflection of the 
diversity of New Jerseys forests. 

The 1 999 inventory also identified 77 species of trees, 
including many that are uncommon. Red maple, the most 
numerous species among trees less than 5 inches in diameter, 
is found to some extent in every forest-type group. Pitch 
pine is the most numerous species in the 6- to 10-inch 
diameter classes, while all oak species combined 
outnumber pitch pine and red maple trees in diameter 
classes above 12 inches. 

The 10 most common species listed in the 
accompanying chart account for 79 percent of the total 
cubic-foot volume of trees in the State. Cubic-foot 
volume is a measure of the amount of wood in the bole 
of a tree between a 1-foot stump and a 4-inch top 
diameter. Pitch pine remained the leading species by 
volume, followed by red maple. However, red maple 
showed the largest increase in volume and likely will 
overtake pitch pine in terms of volume in the near future. 
Together, oak species represent 29 percent of the total 
volume of live trees at least 5 inches in d.b.h. Individual 
species are distributed by how well they are suited to 
particular site conditions. In addition to the factors 
mentioned, the numbers and types of animals present also 
affect species distribution. Deer, mice, and squirrels 
influence forest composition by browsing seedlings, 
consuming available seeds of preferred species, and storing 
seeds that later geminate. For example, deer prefer to 
browse oak rather than red maple and yellow-poplar 

Number of Trees by Diameter Class 

10 12 14 16 18 20 

Diameter class (inches at breast height) 

Area of Timberland by Forest-type Group 

1 000 

Number of Trees for Selected Species, 1 999 




40 - 

20 - 

Pitch pine — 
Red maple — 

Diameter Class (inches at breast height) 

I +47% 

ZH +1% 


Volume of Live Trees Greater Than 5 Inches d.b.h. 

Pitch pine 

Red maple 

Other red oaks 


9! Northern red oak 

,9- White oak 



Other white oaks* 
Atlantic white-cedar 

■ 1987 
□ 1999 







Million cubic feet 

Includes chestnut and post oak. 


Relative Importance of Five Common Tree Species Across New Jersey 
Pitch Pine Red Maple White Oak 

Northern Red Oak Other oaks 

How were these maps created? 

The inventory plots were used as known data. Then the values at unknown locations were predicted from 
information from those plots. For example, an unknown area near a group of plots with large amounts of 
pitch pine probably has high amounts of pitch pine as well. Using this principle, we made predictions at 
every location on the map. The values of relative importance are the percentage of a stand's stocking 
that is composed of that species. The categories used are low (less than 5 percent of a stand's basal 
area), moderate ( 5-19 percent), high (20-49 percent), and very high (50 percent or greater). Stand basal 
area is the total cross-sectional area of trees at breast height-usually calculated as square feet per acre. 


Top 12 shrub species in New Jersey 
(Millions of stems) 

Huckleberry and blueberry are the most abundant shrub in New Jersey's 
forests, turning a bright red in the fall. 

Red maple grows abundantly throughout New Jersey 
except in the Pine Barrens, where wildfires have kept 
populations of this fire-susceptible species low and 
restricted its distribution to wet areas. In the dry, sandy 
soils of the Pine Barrens, pitch pine flourishes and is 
frequently found growing with blackjack and scarlet oak 
and a dense shrub layer of huckleberry and blueberry. As 
with many of the plants that grow here, pine and oak 
species are able to survive and reproduce after fires 
because of their thick bark and ability to sprout from 
stumps when the tree bole is killed. In addition, fire is 
the mechanism that causes the cones of pitch pine to 
open and release their seeds. 


Understory vegetation is an important component of 
forested habitats because it provides both food and cover 
for wildlife. Huckleberry and blueberry are the most 
common shrub species in New Jersey. Barberry, a 

Huckleberry 24,323 

Blueberry 12,802 

Sweet pepperbush 4,550 

Sheep laurel 2,055 

Rose 1 ,087 

Briers/Brambles 930 

Common spicebush 894 

Mountain laurel 736 

Maple-leaf viburnum 573 

Maleberry/Staggerbush 506 

Barberry 443 

Fetterbush 277 

nonnative plant that invades natural plant communities, 
is the eleventh most common shrub growing in the 
State's forests. High deer populations contribute to the 
spread of barberry because it is browsed infrequently. 

The Changing Face of 
New Jersey's Forest Habitat 

The types and number of wildlife species that 
inhabit a forest change as it matures. In the 
seedling-sapling stage that follows major 
disturbances such as clearcutting, fire, and land 
abandonment, many wildlife species use low- 
growing herbaceous and shrub vegetation. 
Species that prefer this type of habitat include 
the American goldfinch, cedar waxwing, song 
sparrow, and eastern cottontail. As larger trees 
become established and shade out much of the 
low-growing vegetation, species that depend on 
this early pioneer vegetation decline in number 
as others that use the boles of trees move into 
the area. This intermediate stage corresponds to 
the poletimber-size class. Many poletimber 
stands lack the low-growing vegetation of the 
regeneration stage and the tree boles lack the 
bark flaps, cavities, and other bole 
characteristics that develop as a stand matures. 
As a result, the number of species present is low 
between the dense thicket vegetation of the 
regeneration stage and the mature or 
sawtimber-size class, which is dominated by 
large trees. The number of species reaches a 
maximum in mature, overmature and all-age 
stands. Species that are more likely to inhabit 
mature stands include the black bear, 
porcupine, and pileated woodpecker. 

New Jersey's forests are maturing. On half of the forest land, sawtimber-size trees 
are the dominate vegetation. 

In New Jersey, the area in the regenerating or seedling- 
sapling stage has decreased because less farm land is 
being allowed to revert to forest. Conversely, the area in 
the mature or sawtimber-size trees has increased because 
low rates of harvesting have contributed to the 
continued growth and maturation of the forest. These 
changes have been accompanied by a remarkable 
recovery and return of many woodland species during 
the last century Population increases have been noted for 
beaver, black bear, white-tailed deer, and wild turkeys. 

Wildlife populations are dependent on the quality of the 
forest habitat. Habitat characteristics that increase as 
stands mature include the size of mast-producing trees 
and the number of standing dead and cull trees. Beech, 

Change in Stand-size Class on Timberland 
and Percentage of Total 










Poletimber Sawtimber 
1972 ■ 1987 □ 1999 





Land reverting to forest from abandon farm 
land offsets forest land lost to development. 
Only a small portion of New Jersey's forest 
land is covered with early successional 
seedling/sapling stands. 

hickory, and the oaks are important mast-producing species. Hard mast such as 
nuts and hard seeds produced by overstory trees is an important forage resource 
for wildlife. Species that depend on acorns and other hard mast include the 
black bear, blue jay, chipmunk, gray fox, red-headed woodpecker, ruffed 
grouse, squirrel, striped skunk, white-tailed deer, and wild turkey. The amount 
of mast produced increases as trees become larger, so it can be assumed that 
mast production has increased in New Jersey with the increase in the number 
of large diameter beech, hickory, and oak. Since 1987, the number of oak and 
beech trees 1 1 inches and larger in diameter has increased by 26 and 23 
percent, respectively. 

Standing-dead and cull trees are important feeding and nesting sites for 
wildlife. These trees have a higher probability of being used by primary cavity 
nesters such as woodpeckers as their wood is more easily 
excavated. These and natural cavities caused by disease or injury 
are used as resting or nesting sites by various species of birds and 
small mammals. In New Jersey, 8 percent of all standing trees 
more than 5 inches in d.b.h. are dead. On average, there are 1 5 
dead trees 5.0 inches or larger in diameter per acre of timberland. 
A third of the dead trees are species of oak. 

Cull trees, which also are important to wildlife, exceed 
maximum allowances for defects for use as timber products. Yet 
some of the same characteristics that make these trees undesirable 
for timber products are beneficial to wildlife. Examples include 
cavities, broken tops, pockets of rot, and boles with numerous 
forks and limbs. On average, there are 16 cull trees per acre of timberland. 

Number of Dead and Cull Trees Per Acre 

5.0-10.9 11.0-14.9 15+ 

Diameter (inches at breast height) 



Trees play an important role in the world's carbon cycle. 
They act as a sink for carbon, removing it from the 
atmosphere in the form of carbon dioxide (a greenhouse 
gas) and storing it as cellulose. In this role, forests help 
mitigate the effect of burning fossil fuels and the 
resulting global climate change associated with increased 
levels of carbon dioxide in the atmosphere. In New 
Jersey, because of increases in tree volume, the State's 
forests contribute greatly to the sequestration of carbon. 

Woody biomass, a measure of how much carbon is being 
stored on forest land, is the total weight of both live and 
dead trees, including branches, roots, and stumps, plus 
the weight of shrubs. The total dry weight of all biomass 
on New Jersey's timberland equals 135 million tons or 83 
tons per acre. The largest portion of this amount (55 
percent) is contained in the merchantable boles of 
commercially important trees. It is this component that 
can be converted to high-value wood products. Other 
portions of biomass are underutilized and can be 
considered as a potential source of fuel for commercial 
power generation. Because it is a renewable source of 
energy, biomass could help reduce the Nation's 
dependence on fossil fuels. In some regions of the 
country, the use of biomass to fuel commercial power 
generating plants has provided markets for low-grade 
trees and other waste wood. 

Sustainability and Use of New Jersey's 

Well-tended forests supply a continuous flow of products 
without impairing long-term productivity. Unlike coal 
and oil, forests are alive and renewable. One way to judge 
the sustainability of a forest is to look at the components 
of inventory change — growth, removals, and mortality. 

During the last 50 years, the growth of New Jersey's 
forest resource has greatly outpaced losses due to the 
removal of trees by cutting and mortality. Removals 
include trees harvested on land that remains in forest, 
trees lost because the forest was developed for a nonforest 
use, and trees removed from the timber resource base 
because they grow on land where harvesting now is 
restricted. The most recent inventory revealed that since 

Components of Woody Biomass 

1987, on an annual basis, the net growth of trees in New 
Jersey averaged 58 million cubic feet versus 36 million 
cubic feet in removals. This surplus translates to an 
annual net increase of 0.8 percent in the volume of wood 
on the State's timberland. 

Nearly 70 percent of removals are attributed to the 
conversion of forests to nonforest uses; 27 percent is 
attributed to timberland reclassified to reserve status, and 
5 percent to harvesting. Trees regenerate and thrive after 
harvesting so long as the land remains in forest. Forests 
classified as reserved continue to provide benefits other 
than timber products. Converting large amounts of 
forest to nonforest use threatens sustainability because 
such changes usually are permanent. As a result, future 
timber growth from these lands is lost, as are related 
benefits, for example, the recharge of groundwater 
aquifers. Loss of forest land to development is a growing 
concern in New Jersey as the adverse effects of clearing 
forests for development are cumulative over time. By 
contrast, forests recover from sustainable timber harvests. 
Because harvesting represents only 3 percent of the 
annual net growth, it has few impacts on the State's 
timber resource. New Jersey currently has few sawmills, 
so a large portion of the harvested trees is shipped to 
mills in Pennsylvania and New York. The lack of markets 
for raw wood products makes it more difficult for forest 
owners to generate profits from their land and increases 
the likelihood that these tracts will be converted to other 
nonforest uses. 

In addition to insects and diseases, disturbances such as 
fire, wind, and competition among trees contribute to 
tree mortality. The volume of trees that die from causes 


Despite the use of state-of-the-art equipment and 
technology, wildfires have burned thousands of 
acres of New Jersey's forests during drought years. 

Courtesy of New Jersey Forest Fire Service 

other than cutting is reported as mortality. In 
1999 in New Jersey, average annual mortality 
was 16.8 million cubic feet or 0.6 percent of 
the inventory volume. This rate, similar to 
those in neighboring states, is considered 
normal. Generally, mortality rates were higher 
for trees less than 1 1 inches d.b.h. than for 
larger diameter trees; mortality rates were 
higher for softwood than for hardwood 
species. In many instances, the smaller trees 
that died were understory trees that were 
crowded out by larger trees. As trees become 
larger, fewer can grow on each acre of forest 

1 00.0 

Potential Supply of Timber 

New Jersey has untapped potential with respect to its 
timber resource. In 1999, the potential amount of 
sawtimber available for harvesting totaled 8.1 billion 
board feet, an increase of 44 percent since the 1987 
inventory. This total is equivalent to the amount of wood 
in a half million houses. The large increase in volume was 
attributed primarily to the many poletimber-size trees 
that grew to sawtimber size. Hardwood species account 
for 83 percent of the total board-foot volume. Yellow- 
poplar and pitch pine were the leading species in 
sawtimber volume; the oak species accounted for a third 
of the volume. 

Components of Annual Volume Change on 
Timberland 1987-1999 

7 5.1 





Gross Growth Mortality Net Growth Removals Net Change 

68% due to land use changed to nonforest use 
27% due to land use changed to reserved forest land 
5% due to harvesting 

Mortality Rates 

Trees 5 to less 
than 1 1 inches 

Trees 1 1 
inches and 
larger in 

All trees 5 
inches and 
larger in d.b.h. 









All species 





Potential Available Sawtimber Volume, 1987 and 1999, With 
Percentage Change Between Inventories 

Pitch pine 
Other red oaks 
Red maple 
Northern red oak 
White oak 
Other white oaks 
Atlantic white-cedar 

□ +65% 



J +95% 



■ 1987 
□ 1999 


200 400 600 800 1000 
Million board feet 


Forest Health 

Forests are continually stressed by insects, diseases and 
other factors that reduce growth and increase tree 
mortality. How forests withstand them is a measure of 
their overall health. To a great extent, New Jersey's forests 
have overcome these stresses as trees have continued to 
increase in number, size, and volume. An increasing 
threat to forest health is the introduction of exotic 
insects, diseases, and plants from overseas. Introduced 
species typically have few natural enemies in this country, 

so unchecked populations can explode under the right 

The loss of the American chestnut to the chestnut 
blight in the early 1900's and the demise of the 
American elm to the Dutch elm disease later in the 
century demonstrate the destructive nature of 
nonnative exotic species. Introduced diseases that are 
not as well known are the butternut canker, which is 
slowly eliminating butternut trees from the Nation's 
eastern forests, and dogwood anthracnose, which has 
greatly reduced the populations of dogwood trees in 
the forest understory. Since the late 1960s, periodic 
outbreaks of the gypsy moth caterpillar have 
defoliated thousands of acres of forest, resulting in 
large losses of tree growth and extensive tree mortality. 
White oak is particularly susceptible to gypsy moth. 

The hemlock woolly adelgid (HWA) and the elongated 
hemlock scale, introduced to the United States from 
Asia, are causing widespread mortality of eastern 
hemlock trees. The HWA has been destroying hemlock 
stands in New Jersey for more than two decades. Many 
hemlocks grow in nearly pure stands in ravine forests in 
the northern part of the State. The loss of dense shade 
provided by these trees can alter the ecology of streams in 

The hemlock woolly adelgid, an 
introduced pest, is killing hemlock 
trees in northern New Jersey. 
Without the dense shade provided 
by hemlocks, streams warm in the 
sun and become unsuitable for trout. 

ravines. Because the HWA and hemlock scale feed on the 
juices in the hemlock needles, chemical spraying to 
control these pests is ineffective. Currently, a predatory 
beetle that is a natural enemy of the HWA in Asia is 
being released in the State. Another destructive forest 
insect pest, the Asian longhorn beetle, was detected in 
Jersey City in 2002. Thought to have arrived in the 
United States in the wood of shipping pallets, the beetle 
feeds on a variety of hardwood trees, including maples 
and ash. Intense efforts are underway to prevent this 
species from establishing itself in the State. To date, the 
Asian longhorn beetle can be eliminated only by 
removing infested trees and destroying them by chipping 
or burning. 

Air pollution and climate change are long-term threats to 
the health of a forest. Air pollutants such as ozone can 
distress foliage and acid deposition can alter the soil 
chemistry. A warming of the climate could result in a 
shift in the range of certain tree species that thrive in cool 
weather. Species such as sugar maple would migrate 
northward out of New Jersey, making growing conditions 
favorable to other species. 

To assess long-term forest health, the Forest Service 
carefully measures selected indicators that can help 
scientists detect when trees are under stress and which 
species are most susceptible. These include crown 
dieback, ozone injury, lichen communities, and soil 
conditions. The accumulate data from these annual 
measurements should provide increasingly accurate 
assessments of the health of New Jersey's forests. 

The Future of New Jersey's Forests 

In general, New Jersey's forests are healthy and resilient, 
and will continue to mature. Current trends indicate that 
the State's future forests will have larger trees, higher 
volumes per acre, and more old-growth characteristics. 
But these forests will be vastly different from the original 
forests that confronted the early settlers. As the Garden 
State's economy and population grow, the impact on the 
forest resource will only increase. Land cleared for 
development will remain in this condition permanently 
even as more land is cleared. Fragmentation of forests 
into ever smaller patches will continue, rural areas will 

become more urbanized, and the introduction of 
unwanted invasive insect, disease, and exotic plant 
species will continue to threaten native species. Once 
established, many nonnative species become a permanent 
part of the ecosystem they inhabit. The adverse effects of 
these changes may not be immediately evident, and the 
overall impact may be difficult to assess because forests 
change slowly. 

High deer populations are causing changes in species 
composition and hindering the ability of forests to 
reproduce. Natural processes within the forest are 
disrupted by interference by humans. For example, 
increased efforts to control wildfires as homes and new 
developments encroach on forests, breaking the natural 
fire cycle to which the State's pinelands are adapted. As a 
result, in the Pine Barrens, pine eventually could lose its 
dominance to hardwood species. 

Threats to New Jersey's forest from beyond its borders 
include pollutants carried into the State by wind, and 
possible changes in climate. These and other factors will 
make it increasingly difficult to manage the Garden 
State's forests. As threats to forest health increase, the 
monitoring and tending of forest land will become more 
important. Attempts now underway to keep hemlock 
trees from disappearing and to control Asian longhorn 
beetles are examples of management activities that will 
become more common in the future. 

Attention to the urban forest will increase our 
understanding of how trees benefit society. Programs 
designed to build, maintain, and enhance the urban 
forest likely will expand, as will community 
commitments to protect the State's urban-suburban 
forests. Regarding trees as a valued element of the urban 
infrastructure will result in a better managed resource 
that will improve the aesthetics and livability of New 
Jersey's cities and towns. 

The area of forest in the State has peaked as the area of 
new forests from abandoned agricultural lands now is 
being outpaced by development. In reaction to this, 
forests in public ownership probably will continue to 
expand. Land trusts, nonprofit organizations, and public 


^ 12/1 1/01 10:07am'' 

r"* 'IBKBi 

Thinning understory vegetation 
concentrates future growth on a few 
large trees and reduces the risk of 
destructive crown fires. 

Photos courtesy of New Jersey Division of Parks 
and Forestry - New Jersey Forest Service 

After Thinning 

agencies and government entities are actively pursuing 
protection strategies. Conservation easements allow 
lands to remain in private ownership and protect critical 
habitats for wildlife while providing a continued 
mechanism for forest use. The pace of forest loss will be 
determined by the effectiveness of efforts to identify and 

target for protection undeveloped land that is critical for 
providing benefits such as clean drinking water and 
recreational and aesthetic enjoyment. Should these and 
other programs be successful, New Jersey will become a 
leader in integrating people into a functioning 


Forest Inventory and Analysis, USDA Forest Service, 

Northeastern Research Station 

1 1 Campus Boulevard, Suite 200 

Newtown Square, PA 19073 

(610) 557-4051; 

New Jersey Forest Service 
Division of Parks & Forestry 
PO Box 404 

Trenton, NJ 08625-0404 
Tel. 609-292-2531 dep/ parksandfo rests/ forest/ 

Widmann, Richard H. 2005. Forests of the Garden State. Resour. Bull. NE-163. 
Newtown Square, PA: U.S. Department of Agriculture, Forest Service, 
Northeastern Research Station. 20 p. 

A report on the fourth forest inventory of New Jersey conducted in 1998-99 by the 
Forest Inventory and Analysis unit of the Northeastern Research Station. Discusses 
the current condition and changes from previous inventories for forest area, timber 
volume, tree species, and growth and removals. Graphics depict data at the state 
level and by county where appropriate. 

Keywords: New Jersey; forest inventory; volume; biomass; growth and removals 

"Caring for the Land and Serving People Through Research' 


Printed on Recycled Paper 





Headquarters of the Northeastern Research Station is in Newtown Square, 
Pennsylvania. Field laboratories are maintained at: 

Amherst, Massachusetts, in cooperation with the University of Massachusetts 
Burlington, Vermont, in cooperation with the University of Vermont 
Delaware, Ohio 

Durham, New Hampshire, in cooperation with the University of New Hampshire 
Hamden, Connecticut, in cooperation with Yale University 
Morgantown, West Virginia, in cooperation with West Virginia University 
Parsons, West Virginia 
Princeton, West Virginia 

Syracuse, New York, in cooperation with the State University of New York, 
College of Environmental Sciences and Forestry at Syracuse University 

Warren, Pennsylvania 

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(202)720-5964 (voice and TDD). USDA is an equal opportunity provider and employer. 

Caring for the Land and Serving People Through Research